Real Time Communications over Internet Protocol (IP) has two components: signaling and media. On each device, usually a single IP Address/port pair is used for all signaling. For media (e.g., communication of Real-Time Transport Protocol packets) a different IP Address/port pair is used for each session. If control packets are used for media (e.g., communication of Real-Time Transport Control Protocol packets) these also consume another IP Address/port pair. Furthermore, a communication session may consist of several components such as for example, audio and video, and each component consumes an IP Address/port pair. While there are some mechanisms to bundle all components/control packets so that they consume a single IP Address/port pair, these mechanisms are not widely deployed, and their use does not change the fact that for each communication session media consumes at least an IP Address/port pair. FIG. 1A illustrates a real time communication entity/network device 160 in which signaling 180, for example control signaling such as Session Initiation Protocol packets, are communicated to/from the Internet Protocol address/port pair IP-1/port-1 180 on real time communication entity/network device 160, while media for communications session-1 182 is communicated to/from IP address/port pair IP-1/port-2 164, media for communications session-2 184 is communicated to/from IP address/port pair IP-1/port-3 166, media for communications session-3 186 is communicated to/from IP address/port pair IP-1/port-4, . . . , media for session-N 188 is communicated to/from IP address/port pair IP-1/port-N+1 170. The control signal and the media for each of the sessions supported by the real time communications entity 160 requires the use of an IP address/port pair.
Many systems use Real-Time Transport Protocol over User Datagram Protocol (UDP) for the communication of media. The destination port field in the UDP header is 16 bits which limits the maximum number of ports to 65536. This means that a single IP address can only be used for media components of 6556 simultaneous communication sessions. The media component of the next communication session requires the use of a new IP Address.
When dealing with consumer endpoints in the Internet domain, network elements need to use public IP Addresses so that they can send and receive IP packets. Internet Protocol version 4 (IPV4 is the dominant IP version currently in use for the Internet and it is scarce due to its 32 bit address field.
There are additional issues which are particularly relevant for Session Border Controller (SBC) cloud deployments when it comes to excessive use of IP addresses. Certain redundancy schemes utilize modestly sized Virtual Machines (VMs) to achieve better failover characteristics and performance. However, these redundancy schemes increase the number of total Virtual Machine instances and using a public IP address for each instance is not a preferable option as it would inefficiently use the scarce IP addresses.
In addition, there is also the issue of large broadcast domains in large cloud deployments utilizing Overlay Networks. These Overlay Networks provide OSI Layer-2 (data link layer) semantics across Virtual Machine instances distributed across various subnets by using various tunneling technologies. Each virtual machine instance being a software implementation that emulates a physical computer system. The larger the number of IP Addresses used the greater the burden of the broadcast traffic. This is an issue with both Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6).
From the above discussion, it should be appreciated that there is a need for improved methods and apparatus for efficiently managing the use of IP addresses and for communications solutions that reduce the number of public IP addresses used. Furthermore, there is a need for methods and apparatus that reduce the number of public/routable IP addresses used by Virtual Machine instances. These are Internet and communication centric problems concerning how to efficiently use and manage the limited number of Internet Protocol addresses available.